doc_rst: rename the media Sphinx suff to Documentation/media

The name of the subsystem is "media", and not "linux_tv". Also,
as we plan to add other stuff there in the future, let's
rename also the media uAPI book to media_uapi, to make it
clearer.

No functional changes.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

1 files changed, 113 insertions, 0 deletions

diff --git a/Documentation/media/uapi/v4l/vidioc-g-crop.rst b/Documentation/media/uapi/v4l/vidioc-g-crop.rst
new file mode 100644
index 000000000000..6cf76497937c
--- /dev/null
+++ b/Documentation/media/uapi/v4l/vidioc-g-crop.rst
@@ -0,0 +1,113 @@
+.. -*- coding: utf-8; mode: rst -*-
+
+.. _VIDIOC_G_CROP:
+
+**********************************
+ioctl VIDIOC_G_CROP, VIDIOC_S_CROP
+**********************************
+
+Name
+====
+
+VIDIOC_G_CROP - VIDIOC_S_CROP - Get or set the current cropping rectangle
+
+
+Synopsis
+========
+
+.. cpp:function:: int ioctl( int fd, int request, struct v4l2_crop *argp )
+
+.. cpp:function:: int ioctl( int fd, int request, const struct v4l2_crop *argp )
+
+
+Arguments
+=========
+
+``fd``
+    File descriptor returned by :ref:`open() <func-open>`.
+
+``request``
+    VIDIOC_G_CROP, VIDIOC_S_CROP
+
+``argp``
+
+
+Description
+===========
+
+To query the cropping rectangle size and position applications set the
+``type`` field of a :ref:`struct v4l2_crop <v4l2-crop>` structure to the
+respective buffer (stream) type and call the :ref:`VIDIOC_G_CROP <VIDIOC_G_CROP>` ioctl
+with a pointer to this structure. The driver fills the rest of the
+structure or returns the ``EINVAL`` error code if cropping is not supported.
+
+To change the cropping rectangle applications initialize the ``type``
+and struct :ref:`v4l2_rect <v4l2-rect>` substructure named ``c`` of a
+v4l2_crop structure and call the :ref:`VIDIOC_S_CROP <VIDIOC_G_CROP>` ioctl with a pointer
+to this structure.
+
+Do not use the multiplanar buffer types. Use
+``V4L2_BUF_TYPE_VIDEO_CAPTURE`` instead of
+``V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE`` and use
+``V4L2_BUF_TYPE_VIDEO_OUTPUT`` instead of
+``V4L2_BUF_TYPE_VIDEO_OUTPUT_MPLANE``.
+
+The driver first adjusts the requested dimensions against hardware
+limits, i. e. the bounds given by the capture/output window, and it
+rounds to the closest possible values of horizontal and vertical offset,
+width and height. In particular the driver must round the vertical
+offset of the cropping rectangle to frame lines modulo two, such that
+the field order cannot be confused.
+
+Second the driver adjusts the image size (the opposite rectangle of the
+scaling process, source or target depending on the data direction) to
+the closest size possible while maintaining the current horizontal and
+vertical scaling factor.
+
+Finally the driver programs the hardware with the actual cropping and
+image parameters. :ref:`VIDIOC_S_CROP <VIDIOC_G_CROP>` is a write-only ioctl, it does not
+return the actual parameters. To query them applications must call
+:ref:`VIDIOC_G_CROP <VIDIOC_G_CROP>` and :ref:`VIDIOC_G_FMT`. When the
+parameters are unsuitable the application may modify the cropping or
+image parameters and repeat the cycle until satisfactory parameters have
+been negotiated.
+
+When cropping is not supported then no parameters are changed and
+:ref:`VIDIOC_S_CROP <VIDIOC_G_CROP>` returns the ``EINVAL`` error code.
+
+
+.. _v4l2-crop:
+
+.. flat-table:: struct v4l2_crop
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       1 1 2
+
+
+    -  .. row 1
+
+       -  __u32
+
+       -  ``type``
+
+       -  Type of the data stream, set by the application. Only these types
+	  are valid here: ``V4L2_BUF_TYPE_VIDEO_CAPTURE``,
+	  ``V4L2_BUF_TYPE_VIDEO_OUTPUT`` and
+	  ``V4L2_BUF_TYPE_VIDEO_OVERLAY``. See :ref:`v4l2-buf-type`.
+
+    -  .. row 2
+
+       -  struct :ref:`v4l2_rect <v4l2-rect>`
+
+       -  ``c``
+
+       -  Cropping rectangle. The same co-ordinate system as for struct
+	  :ref:`v4l2_cropcap <v4l2-cropcap>` ``bounds`` is used.
+
+
+Return Value
+============
+
+On success 0 is returned, on error -1 and the ``errno`` variable is set
+appropriately. The generic error codes are described at the
+:ref:`Generic Error Codes <gen-errors>` chapter.